Thomson Tubes Electroniques

Renault Trucks

Alain Tranchant

Gerard Vieux

Francois Chareyre

Yves Raverdy

Jean Michel Fortier

Patrick Paletto

Hoang Giang Nguyen

An image intensifying tube, such as a image intensifying tube which converts X-rays into a visible image, comprises a curved input screen which comprises a substrate that receives input radiation and a photocathode supported on the substrate, and an output screen which converts the electrons emitted by the photocathode into a visible image. In order to compensate for changes in luminosity due to the curvature of the input screen, an intermediary layer of radially variable thickness is deposited between the substrate and the photocathode. The intermediary layer is made from a material, such as indium oxide (In.sub.2 O.sub.3), which modifies the electron emitting characteristics of the photocathode as a function of the thickness the intermediary layer. Thus, a thicker intermediary layer near the center of the input screen will compensate for reduced luminosity at the edges of the screen.

Input screen of a radiographic image intensifying tube having a radially

Growing community of inventors

St Martin d'Heres, France

Alain Tranchant